books.google.com - Did you know that a groundhog is really a type of squirrel? That squirrels control their body temperature with their tails? That most squirrels have yellow-tinted eye lenses that work like sunglasses to reduce glare? That tree squirrels can turn their hind feet completely around when climbing down a...http://books.google.com/books/about/Squirrels.html?id=-WntqgZjdUgC&utm_source=gb-gplus-shareSquirrels